title: Actions of vasoactive drugs on human placental vascular smooth muscle.
abstract: 1. The effect of different vasoactive agents on segments of human chorionic arteries and veins was analyzed. 2. The order of these agents to produce maximal contractile responses was: 5-hydroxytryptamine (5-HT) = histamine (H) = K+ greater than noradrenaline (NA) greater than or equal to phenylephrine (PHEN) greater than clonidine (CLON), and with regard to their potencies (EC50 values) was: 5-HT greater than or equal to NA greater than or equal to H greater than PHEN greater than CLON greater than K+. Dopamine and isoproterenol did not elicit any type of response. 3. The receptors involved on the contractions elicited by agonists were analyzed. 4. The results obtained suggest that: (1) 5-HT is the most potent vasoconstrictor agent of all those tested, whose effects appear to be mediated by 5-HT2- but not by alpha 1-adrenergic receptors; (2) chorionic vessels also possess H1-receptors; and (3) ketanserin has more affinity to block 5-HT2-receptors than to block alpha 1-adrenergic- and H1-receptors.
authors.affiliation: Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad de Extremadura, Madrid, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Reviriego
authors.forename: M S
authors.initials: MS
authors.lastname: Fernandez-Alfonso
authors.forename: J
authors.initials: J
authors.lastname: Marín
mesh_terms: D001158:Arteries / Q000187:drug effects; D003000:Clonidine / Q000494:pharmacology; D004155:Diphenhydramine / Q000494:pharmacology; D004298:Dopamine / Q000494:pharmacology; D005260:Female; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D009129:Muscle Tonus / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D010920:Placenta / Q000098:blood supply*; D011247:Pregnancy; D012039:Regional Blood Flow / Q000187:drug effects; D012701:Serotonin / Q000494:pharmacology; D014680:Veins / Q000187:drug effects
chemical_list: D010656:Phenylephrine; D012701:Serotonin; D006632:Histamine; D004155:Diphenhydramine; D003000:Clonidine; D004298:Dopamine; D009638:Norepinephrine